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/*
* Copyright (c) 2013 Richard Braun.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef _KERN_BITMAP_I_H
#define _KERN_BITMAP_I_H
#include <limits.h>
#include <kern/macros.h>
#define BITMAP_LONGS(nr_bits) DIV_CEIL(nr_bits, LONG_BIT)
/*
* Adjust the bitmap pointer and the bit index so that the latter refers
* to a bit inside the word pointed by the former.
*
* Implemented as a macro for const-correctness.
*/
#define bitmap_lookup(bmp, bitp) \
MACRO_BEGIN \
int i; \
\
i = BITMAP_LONGS(*(bitp) + 1) - 1; \
*(bmp) += i; \
*(bitp) -= i * LONG_BIT; \
MACRO_END
static inline unsigned long
bitmap_mask(int bit)
{
return (1UL << bit);
}
/*
* Return the index of the next set bit in the bitmap, starting (and
* including) the given bit index, or -1 if the bitmap is empty. If
* complement is true, bits are toggled before searching so that the
* result is the index of the next zero bit.
*/
int bitmap_find_next_bit(const unsigned long *bm, int nr_bits, int bit,
int complement);
#endif /* _KERN_BITMAP_I_H */
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